1、Designation: D3717 85a (Reapproved 2015)Standard Test Method forLow Concentrations of Antimony in Paint by AtomicAbsorption Spectroscopy1This standard is issued under the fixed designation D3717; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the contentof antimony in the range between 50 a
3、nd 200 ppm (mg/kg)present in the solids of liquid coatings or in dried filmsobtained from previously coated substrates. There is no reasonto believe that higher levels could not be determined by thistest method, provided that appropriate dilutions and adjust-ments in specimen size and reagent quanti
4、ties are made.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to
5、establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD2832 Guide for Determining Volatile and Nonvol
6、atile Con-tent of Paint and Related Coatings3. Summary of Test Method3.1 The sample of liquid coating or dried film is preparedfor analysis by dry ashing at 500C, followed by refluxing withhydrochloric acid and stannous chloride. The antimony contentof the acid extract is determined by atomic absorp
7、tion spec-troscopy.4. Significance and Use4.1 The permissible level of heavy metals in certain coat-ings is specified by governmental regulatory agencies. This testmethod provides a fully documented procedure for determininglow concentrations of antimony present in both water- andsolvent-reducible c
8、oatings to determine compliance.5. Apparatus5.1 Atomic Absorption Spectrophotometer, consisting of anatomizer and either a single- or three-slot burner; gas pressureregulating and metering devices for air and acetylene; anantimony source lamp with a regulated constant current supply;a monochromator
9、and associated optics; a photosensitivedetector connected to an electronic amplifier; and a readoutdevice.5.2 Muffle Furnace, maintained at 500 6 10C.5.3 Oven, maintained at 105 6 2C.5.4 Hot-Plate, with variable surface temperature controlover the range from 70 to 200C.5.5 Reflux Condenser, water-co
10、oled, and fitted with astandard-taper joint.5.6 Erlenmeyer Flask, 125-mL, with standard-taper joint tofit condenser.5.7 Volumetric Flasks, 100 and 1000-mL.5.8 Dropping Bottles, 8 or 15-mL (14 or12-oz) capacity.5.9 Glass or Disposable Syringes, 10-mL capacity.5.10 Pipets, 1, 5, 10, and 15-mL capacity
11、.5.11 Filter Paper, ashless, medium or slow filtering.5.12 Paint Shaker.5.13 Paint Draw-Down Bar.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on An
12、alytical Reagents of the American Chemical Society,1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition app
13、roved June 1, 2015. Published June 2015. Originallyapproved in 1978. Last previous edition approved in 2010 as D3717 85a (2010).DOI: 10.1520/D3717-85AR15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMS
14、tandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1where such specifications are available.3Other grades may beused, provided it is first ascert
15、ained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent grade waterconforming to Type II of Specification D1193.6.3 Antimony Standar
16、d Stock Solution (0.1 mg/mL)Dissolve 0.1000 g of antimony metal in 40 mL of sulfuric acid(H2SO4, sp gr 1.84) by heating. Cool, carefully transferquantitatively to a 1-L volumetric flask already approximatelyhalf full with water, allow to cool to room temperature, anddilute to 1 L.6.4 Hydrochloric Ac
17、id (sp gr 1.19)Concentrated hydro-chloric acid (HCl).6.5 Stannous Chloride Solution (400 g/L in HCl)Dissolve40 g of tin (II) chloride (SnCl2) in 50 mL of HCl (sp gr 1.19).Transfer to a 100-mL volumetric flask and fill to the mark withconcentrated HCl.7. Hazards7.1 Use care in handling concentrated H
18、Cl because it iscorrosive and may cause burns to the skin and eyes and itsvapor is irritating to mucous membranes. Refer to suppliersSafety Data Sheet.7.2 Use only a rubber bulb aspirator for pipetting liquids.8. Calibration and Standardization8.1 Prepare 100-mL quantities of at least four standards
19、olutions bracketing the expected antimony concentration inthe sample to be tested. To suitable aliquots of the 0.1 mg/mLstandard antimony solution, add 40 mL of concentrated HCland 8 drops of SnCl2solution. Dilute to 100 mL with water.Prepare a blank solution by diluting 40 mL of concentratedHCl and
20、 8 drops of SnCl2solution to 100 mL with water.8.2 Operational instructions for atomic absorption spectro-photometers vary with different models. Consult the manufac-turers literature for establishing optimum conditions for thespecific instrument used.8.3 Turn the instrument on and set the wavelengt
21、h to the217.6-nm antimony line. Apply the recommended current tothe antimony source lamp. Allow the instrument to warm upfor about 15 min and set the slit width. Adjust the air andacetylene pressures and ignite the burner in accordance withinstructions.8.4 Aspirate water to rinse the atomizer chambe
22、r. Aspirate astandard solution and make any necessary readjustment ininstrument parameters to obtain maximum absorption.8.5 Aspirate the blank solution. When the recorder, meter,or other readout device reaches a constant value, it should beimmediately zeroed. Repeat this blank determination until as
23、teady, repeatable zero value is obtained at the maximumresponse.8.6 Aspirate each of the appropriate standard solutions inascending antimony concentrations and record the correspond-ing instrument readings.Aspirate water between each standard.NOTE 1A deuterium background corrector, if available, sho
24、uld beused to correct for background absorption. If not available, it is necessaryto reaspirate each standard solution and measure the background at anearby nonabsorbing region of the spectrum.NOTE 2Because of the high concentration and corrosive nature of theacids used for the analysis, it is essen
25、tial that the burner assembly bedisassembled and thoroughly cleaned out immediately after the analysesare completed. Consult the instrument manual for cleaning instructions.8.7 Construct a calibration curve on linear graph paper byplotting the absorbance (corrected for background) versusconcentratio
26、n (micrograms per millilitre) for each standardsolution.9. Procedure9.1 If the sample is a liquid coating, mix it untilhomogeneous, preferably on a mechanical paint shaker. Deter-mine the nonvolatile content in accordance with Guide D2832.9.2 Prepare at least two replicate samples by weighing bydiff
27、erence from a dropping bottle or syringe, 5 to 10 g of themixed liquid coating, or by directly weighing approximately 2to6gofdried film, into 125-mL Erlenmeyer flasks. Weigh tothe nearest 0.1 mg.NOTE 3The specimen size called for will have a concentration ofapproximately 4 to 12 g/mL antimony in the
28、 final diluted solution forpaints containing approximately 200 ppm (mg/kg) antimony based on thenonvolatile content, and 1 to 3 g/mL for paints containing approximately50 ppm antimony, based on the nonvolatile content.NOTE 4Recover dried paint films from previously coated substrates(being careful no
29、t to remove any underlying material from the substrate)or prepare in the laboratory from liquid samples. For the laboratorypreparation, flow some of the well-mixed sample onto a clean glass plate.The use of a paint draw-down bar is recommended to obtain a uniformfilm thickness not exceeding 2 mils (
30、50 m). Allow the film to dry in anoven at 105C for a minimum of 1 h. Scrape the dried film off the glassplate, preferably with a single-edge razor blade.9.3 Place the flasks containing the liquid coating on the hotplate and slowly increase the temperature until the material isdried.9.4 When the samp
31、le appears to be dry, or when startingwith a dried film, gradually increase the temperature of the hotplate until the material chars.9.5 After charring appears complete, place the flasks in themuffle furnace and ash at 500C. When the ashing appears tobe complete (approximately 1 to 2 h), remove the
32、flasks fromthe muffle furnace and allow to cool to room temperature.9.6 Carefully add 40 mL of concentrated HCl and 8 drops ofSnCl2solution to each flask. Connect the flasks to water-cooledcondensers and reflux for 1 h.9.7 Filter each digested specimen through medium-porosityfilter paper into a 100-
33、mL volumetric flask. If the filtrate is not3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dor
34、set, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D3717 85a (2015)2clear, refilter through fine-porosity filter paper. Rinse each flaskseveral times with water, adding the rinsings to the filter paper.Wash the filter paper s
35、everal times with water. Adjust thevolume to 100 mL with water and mix.9.8 Aspirate each test solution and determine the absor-bance in the same manner in which the instrument wascalibrated (see Note 1 and Note 2). Determine the concentra-tion of antimony in micrograms per millilitre from the calibr
36、a-tion curve. If the absorbance is above the range covered by thecalibration curve, dilute an aliquot of the test solution to asuitable volume with water containing 40 mL of HCl and 8drops of SnCl2solution per 100 mL. If the absorbance is belowthe range covered by the calibration curve, repeat the a
37、nalysisusing a larger specimen size.NOTE 5Increased sensitivity may be obtained with instrumentspossessing scale expansion and concentration readout capability.NOTE 6The method of standard additions may be used to improve theaccuracy of the analysis. This method is particularly recommended for usewi
38、th unknown samples where matrix effects may be potentially signifi-cant. For a detailed description of the procedure and calculations used inthe method of standard additions, consult a standard text on atomicabsorption spectroscopy or the instruction manual provided by theinstrument manufacturer.10.
39、 Calculation10.1 Calculate the mean concentration of antimony in thenonvolatile portion of the sample as follows:Antimony, ppm mg/kg! in nonvolatile 5 C 3F 3104!/NV 3S!(1)where:C = concentration of antimony in the aspirated testsolution, g/mL,F = dilution factor from 9.8 (volume diluted to/volume of
40、aliquot),NV = percent nonvolatile of paint sample (use 100 if samplewas dried film), andS = grams of sample.11. Report11.1 Report the antimony content of the nonvolatile contentof the sample and whether the analysis was conducted on aliquid coating or a dried film.12. Precision and Bias412.1 The pre
41、cision estimates are based on an inter-laboratory study in which eight different laboratories analyzedin duplicate, on two different days, three samples of water-reducible paints and three samples of solvent-reducible paintscontaining from 50 to 200 ppm (mg/kg) antimony. Thewithin-laboratory coeffic
42、ient of variation was found to be4.8 % relative at 31 degrees of freedom and the between-laboratory coefficient of variation was 8.8 % relative at 25degrees of freedom. Based on these coefficients, the followingcriteria should be used for judging the acceptability of resultsat the 95 % confidence le
43、vel:12.1.1 RepeatabilityTwo results, each the mean of dupli-cate determinations, obtained by the same operator on differentdays, should be considered suspect if they differ by more than14 % relative.12.1.2 ReproducibilityTwo results, each the mean of du-plicate determinations, obtained by operators
44、in differentlaboratories, should be considered suspect if they differ bymore than 26 % relative.12.2 BiasThe mean of duplicate determinations withinany laboratory should be within 18 % relative of true value.13. Keywords13.1 AAS, antimony; low concentration of antimony inpaintsASTM International tak
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48、e address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (ph
49、one), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D01-1011. ContactASTM CustomerService at serviceastm.org.D3717 85a (2015)3
